The invention relates to a cathode ray tube comprising an electron gun, a display screen provided on an inner surface of an at least substantially rectangular curved display window and a colour selection electrode arranged in front of the display screen.
The invention also relates to a color display device comprising a cathode ray tube.
Such cathode ray tubes are known. In operation, the electrons of an electron beam emitted by the electron gun impinge on the color selection electrode, thereby heating it. Approximately 80% of all electrons are captured by the color selection electrode. The heating of the color selection electrode causes the electrode to expand. As a result the apertures in the color selection electrode are displaced relative to the display screen. This phenomenon is called "doming". One type of doming is the so-called local doming. Local doming occurs as a result of differences in the intensity of the image displayed. As a result, certain parts of the color selection electrode are heated more than others, thereby causing the color selection electrode to bulge locally, which brings about color errors.